Relationship between He (and equivalent 3He) and TiO2 content of lunar regolith samples (data from Apollo and Luna missions). The average in-situ 3He grade of the regolith at Mare Tranquillitatis at >7.5 wt% TiO2 (sampled at the Apollo 11 landing site) is estimated at around 20 ppb 3He, due to losses during sampling, transport and laboratory handling on Earth.

Comparison of grade and value of 3He in Moon regolith to grade and stone value of major hard-rock diamond mines on Earth. In-situ ore value of Moon regolith is at the lower margin of terrestrial diamond ore which ranges from 10-200 USD/t.